Production of bifunctional carbqnyl



UNITED PATENT ors-[cs ,BRQDUC HON F BIFUNCTIONAL CARBQNYL COMPQUNDSIEBQM :D QH 0 0BUF1A E Alfred L. Miller, .Summit, 1N. jJ ,and "Bernard "H.

K 'QS m ledmzQhio, assignors to Cela-n e se Corvporation of America, New YorkgN. *Y., a corpoir i nofDelawat No Drawing. ApplicationApril'29, 1951.9, Serial No. $10,556

.,2=,Claims. l This invention relates to the preparation {Of compounds containing an aldehyde group and relates more particularly to an-improyed :process for the production of bis-diacetals, whichmay'be halide,high temperatures of about 80-'to-100 C.

or more,a cobalt salt catalyst, and finely-divided magnesium during the preparation of the Grignard reagent, an intermediate coupling reaction readily hydrolyzed to yield 'the corresponding di 5 may be favored whereby one mol of the Grignard aldehydes. reagent-formed couples with onemol of the an- An object of this invention is the provision of phatic dihalogenpompound. This coupling rean efficient and economical process :for the actionzresults'in the formation of aGrignardreapreparation of bis-diacetals. .gentwherein-the alkylene :group in the chain is Another object of this invention is the protwice the length of the alkylene chain in the duction of aliphatic dialdehydes from halogeninitialdihalogenated aliphatic compound. Mag- ,ated organic compounds by converting said nesium dihalide isobtained-as a by-product of halogenated organic compounds to bis-diapetals the .couplingreaction. When theGrignard reafollowedby hydrolysiscfsaid'diacetals. gent of increased alkylene chain length which A further object of this invention is to-provide is believed to beformed in'thisfashionis reacted a process for the production of aliphatic dialdewith ethyl orthoformate, for example, the correhydes employing dihalogenated aliphatic com-' sponding longer chain aliphatic diethyl acetal is pounds whereby the aliphatic 'dialdehydes obobtained. On hydrolysis, the latteris converted tained may be of a longer chain lengththanthe to the .longer chain dialdehyde. By our improved dihalogenated aliphatic compounds employed as process, aliphatic dialdehydes of relatively high intermediates. -molecularweightmay be readily obtained.

Other objects of this invention-willzappear from Thus, for example, when '1, i-dichloro-lo-utane the followingdetailed description. isreacted with magnesium in a suitable solvent Aside from glyoxal, the aliphatic ldialdehyde to form .the Grignard reagent, 1,4-butylene-diof lowest molecular weight, dialdchydes have :not magnesium-chloride is obtained as the primary heretofore been readily available since methods reaction product. "Under :favorable conditions, for their production directly and in suitable yield 1-chloro-octylene-8emagnesium-chloride is also have I101; b develeped- Th b unetiona obtained as a secondary reaction product. 'The character of dialdehydes, whether aliphatic, ali- "latter is ibelieved-to be formed by-reaction of a cyclic or-aromatic, renders them of great value 39 part of the 1,4-butylene-di-magnesium-chloride for use in many reactions, and methodswhereby wi-th unreacted lA-dichlcro-butane. 'The sec- Seid mp u d y b ob aine fiici n ly a ondary reaction product apparently undergoes economically andin high yield are of considerable "furtherreaction with the magnesium in :the recommercial importance. action mixture'to-form the 1,8-octylene di-mag- We av w fo d h dieeetels y be 5 nesium-chloride-Grignard reagent. Reaction of readily obtained from the corresponding alpha, the '1,4-butylene-di-magnesiumchlorideand the omega-dihalogenated aliphatic compound or di- 1,8-octylene-di-magnesium chloride Grignard halogenated alicyclic or aromatic compounds by reagents in the reaction mixture with ethyl orconverting the same to the Grignard reagent thoformate yields adipaldehyde-bis-diethylacetal employing magnesium and a suitable solvent un- 40 and sebacaldehyde-bis-diethylaceta1 respectively. der anhydrous conditions, and then reacting the Hydrolysis of said acetals under very mild acid bifunctional Grignard reagent thus formed with conditions results in the formation of free adipan alkyl ester of orthoformic acid, such as, for aldehyde and sebacaldehyde. The respective aceexample, ethyl orthoformate or methyl orthotals are preferably separated from each other by formate to yield the corresponding aliphatic difractionation prior to hydrolysis to avoid subseacetal. Examples of other esters of orthoformic quent separation after hydrolysis. acid which are suitable are propyl orthoformate, The conditions under which the Grignard reisopropyl orthoformate, butyl orthoformate, iso action ordinarily takes place are well known in butyl orthoformate and isoamyl orthoformate. the art. The Grignard reaction is, of course, a Upon hydrolysis of the aliphatic diacetal, the degeneric one and may be effected employing varisired aliphatic d hy e i tained s the hyous halogenated aliphatic compounds such as, for drolysis product. Furthermore, in the case of example, chloro-, bromoand iodo-compounds. alpha, omega-dihalogenated aliphatic com- In the case of dihalogenated aliphatic compounds, pounds, by maintaining rigidly anhydrous conthe alkylene group should contain at least four ditions, employing adequate agitation, excess (11- carbon atoms in the chain since with a lesser alicyclic dihalides. such as cyclohexane dichloride and 1,4-dichloromethyl-cyclohexane, aromatic dihalides such as mor p-dichlorobenzene, 1,4-di-(beta-chloroethyl) benzene. Diethyl ether is normaly employed as the reaction solvent, although other solvents may be employed to replace the ether in whole or in part. We have found that methylal, dipropylformal, or even ethyl orthoformate itself alone or in admixture with any one or more of the solvents mentioned above may be conveniently employed as the reaction solvent.

In order further to illustrate our invention but without being limited thereto, the following ex amples are given:

Example I To a mixture of 560 parts by weight of diethyl ether and 112 parts by weight of magnesium shavings are added about 3 parts by weight of ethyl bromide to initiate the desired Grignard reaction and then 256 parts by weight of 1,4- dichlorobutane are added with cooling while continually stirring the reaction mixture. After the latter addition is complete 666 parts'by weight of ethyl orthoformate are added over about onehalf hour, 660 parts by weight of anhydrous benzene are added and the diethyl ether distilled off, the mixture being maintained under reflux at 65 to 70 C. for 4 hours. When the reaction is completed, the reaction mixture is poured on to crushed ice and the Grignard complex decomposed. Magnesium hydroxy chloride is formed as a by-product. The benzene solution is separated and the water extracted with ether, if desired. The benzene and the ether extracts are dried, the benzene and ether distilled 01f and the remaining product fractionated. Adipaldehyde bis-diethylacetal is obtained in a yield of 35% of theory. The latter has a boiling point of 186 C. at 63 mm. pressure and the index of refraction n is 1.4215. Hydrolysis under mildly acidic conditions, i. e. a pH of about 6, yields adipaldehyde; Sabacaldehyde bis-diethylacetal is also obtained in a yield of about of theory although the reaction conditions employed are not primarily chosen to favor the coupling reaction Wherebyysaid longer chain compound is formed.

The latter has a boiling point of 190 to 193 C. at 53 mm. pressure and an index ofrefraction of 12 1.4320.

Example II To 70 parts by weight of dry diethyl ether containing 12.5 parts by weight of magnesium turnings are slowly added 57.5 parts by weight of 1,5- pentamethylene dibromide. After all of the magnesium has been dissolved, 76 parts by Weight of ethyl orthoformate are slowly added and the reaction mixture heated under reflux for about three hours. The reaction mixture is poured on to ice and the organic layer extracted with ether.

The etherextract is dried, the ether evaporated and-the residue fractionated. Pimelic aldehyde bis-diethylacetal boiling at 100 to 110 C. at 0.3 mm. pressure is obtained. The acetal may be readily hydrolyzed to free pimelic dialdehyde under mild acidic conditions.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that man variations may be made therein without departing from the spirit Of our invention.

Having described our invention, what we desire to secure by Letters Patent is:

1. In a process for the production of bifunctional organic compounds, the steps which comprise converting 1,4-dichlorobutane to the magnesium Grignard reagent at a temperature of about to C., reacting the magnesium Grignard reagent formed with ethyl orthoformate, and separating adipaldehyde bis diethylacetal and sebacaldehyde-bis-diethylacetal from the reaction mixture.

2. In a process for the production of bifunctional organic compounds, the steps which comprise converting 1,4-dichlorobutane to the magnesium Grignard reagent at a temperature of about 80 to 100 0., reacting the magnesium Grignard reagent formed with ethyl orthoformate, separating adipaldehyde bis diethylacetal and sebacaldehyde-bis-diethylacetal from the reaction mixture, and hydrolyzing said acetals to yield the corresponding dialdehydes.

ALFRED L. MILLER. BERNARD H. KRESS.

REFERENCES CITED The following references are of record in the file of this patent:

Post: The Chemistry of Aliphatic Orthoesters, 1943, pages 96 to 105, Reinhold Publishing Corp. 

2. IN A PROCESS FOR THE PRODUCTION OF BIFUNCTIONAL ORGANIC COMPOUNDS, THE STEPS WHICH COMPRISE CONVERTING 1,4-DICHLOROBUTANE TO THE MAGNESIUM GRIGNARD REAGENT AT A TEMPERATURE OF ABOUT 80 TO 100* C., REACTING THE MAGNESIUM GRIGNARD REAGENT FORMED WITH ETHYL ORTHOFORMATE, SEPARATING ADIPALDEHYDE -BIS-DIETHYLACETAL AND SEBACALDEHYDE-BIS-DIETHYLACETAL FROM THE REACTION MIXTURE, AND HYDROLYZING SAID ACETALS TO YIELD THE CORRESPONDING DIALDEHYDES. 